Very lightly butter both sides of each of the 12 baguette slices. When you slice the baguette, do not do it on an angle, but rather straight across for petite rounds. Put the buttered bread in the press for a few minutes, until they are crisp and golden.

Take the baguette toasts out, and divide the chocolate equally onto 6 of the baguette toasts, and the brie onto the other 6. Press each chocolate side together with a brie side, and place the sandwiches back into the panini press for just a minute or two, until the chocolate and brie have heated through and just begun to melt. You don't want to wait for the chocolate and cheese to melt completely, or they'll just run out of the bread.

p.s. If you want something even more decadent this Valentine's, use the same amount of brie and chocolate, but substitute 3 plain croissants for the 12 slices of baguette. The result is a sort of brie-stuffed pain au chocolat.